utf8.cpp

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#include "utf8.h"
 
namespace eve
{
 
namespace {
 
size_t utf8_step(unsigned char c)
{
    if ((c & 0x80) == 0)
        return 1;
    if ((c & 0xE0) == 0xC0)
        return 2;
    if ((c & 0xF0) == 0xE0)
        return 3;
    if ((c & 0xF8) == 0xF0)
        return 4;
    return 1;
}
 
} // namespace
 
size_t utf8_codepoint_count(const std::string &s)
{
    size_t n = 0;
    for (size_t i = 0; i < s.size();)
    {
        const size_t step = utf8_step(static_cast<unsigned char>(s[i]));
        if (i + step > s.size())
            break;
        i += step;
        ++n;
    }
    return n;
}
 
size_t utf8_byte_offset_for_codepoints(const std::string &s, size_t codepoints)
{
    size_t n = 0;
    size_t i = 0;
    while (i < s.size() && n < codepoints)
    {
        const size_t step = utf8_step(static_cast<unsigned char>(s[i]));
        if (i + step > s.size())
            break;
        i += step;
        ++n;
    }
    return i;
}
 
#ifdef EVENGINE_WINDOWS
 
std::string to_utf8(LPCWSTR wstr)
{
    size_t wide_len = wcslen(wstr)+1;
 
    // Get size in UTF-8.
    int utf8_size = WideCharToMultiByte(CP_UTF8, 0, wstr, wide_len, 0, 0, 0, 0);
 
    char *utf8_str = new char[utf8_size];
 
    // Convert to UTF-8.
    int ok = WideCharToMultiByte(CP_UTF8, 0, wstr, wide_len, utf8_str, utf8_size, 0, 0);
 
    std::string ret;
    if (ok)
        ret = utf8_str;
 
    delete[] utf8_str;
    return ret;
}
 
std::wstring to_widestr(const std::string &str)
{
    if (str.empty())
        return std::wstring();
 
    int wide_size = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), (int) str.length(), nullptr, 0);
 
    if (wide_size == 0)
        return std::wstring();
 
    std::wstring widestr;
    widestr.resize(wide_size);
 
    int ok = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), (int) str.length(), &widestr[0], widestr.length());
 
    if (!ok)
        return std::wstring();
 
    return widestr;
}
 
void replace_char(std::string &str, char find, char replace)
{
    int length = str.length();
 
    for (int i = 0; i<length; i++)
    {
        if (str[i] == find)
            str[i] = replace;
    }
}
 
#endif // EVENGINE_WINDOWS
 
} // eve